1. Field of the Invention
This invention generally relates to support structures which are loose at room temperatures and provide no translation or rotational motion at cold temperatures. More specifically, it deals with a structure for use in cold optics which requires mechanically supporting a telescope inside an evacuated housing, the support thermally isolating the telescope from the ambient temperature of the housing.
2. Description of the Prior Art
The prior art discloses many types of supports used to compensate for environmental varying temperatures. For example, in large heat exchangers the temperature difference between the heat exchanger and the support structure varies greatly. The usual way of supporting such heat exchangers is by mounting them on a plurality of circumferentially spaced sliding pad type mountings which, in turn, rest directly on the support structure.
Another way of supporting a structure which is subject to thermal variations is described in British Pat. No. 1,239,323. Therein is shown a structure tailored to prevent expansion or contraction under varying thermal conditions. The structure accomplishes this by providing a support which has a plurality of members coupled together, the members being arranged with their lengths chosen so that their thermal contractions compensate for each other to minimize the overall thermal contraction.
Another type of support structure which is designed to compensate for thermal expansion is described in U.S. Pat. No. 3,606,979 which teaches an expandable support means. A movable mount interacts with a rigid mount circumferentially based about a support ring. Each movable mount includes a four bar linkage arrangement in which the top horizontal bar is connected to a support member. The movable mount compensates for the thermal contraction and expansion of the support members to permit the rigid mount to secure the support ring at varying temperatures.
With regard to telescope mounts, it is known that cone-shaped mounts can be used to support a telescope as disclosed in U.S. Pat. No. 2,864,634. Therein is disclosed a telescope mount which provides a pair of keys longitudinally moveable between the telescope and its support and tapered to force the telescope in and out of the support as the support is tightened.